C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use vs C26000 Cartridge Brass (70/30): The Cold-Workable Standard
Side-by-side engineering comparison of C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use (ASTM B152/B187) and C26000 Cartridge Brass (70/30): The Cold-Workable Standard (ASTM B36). Compare mechanical properties, chemical composition, density, yield strength, international equivalents, and typical applications to select the right material for your project.
Quick Comparison
| Property | C11000 ETP Copper: Electr | C26000 Cartridge Brass (7 |
|---|---|---|
| Standard | ASTM B152/B187 | ASTM B36 |
| Category | Copper Alloy | Brass & Bronze |
| Density | 8.94 g/cm³ | 8.53 g/cm³ |
| Yield Strength | 69 MPa (10 ksi) annealed; 310 MPa (45 ksi) hard | 75-420 MPa |
| Tensile Strength | 220 MPa (32 ksi) annealed; 380 MPa (55 ksi) hard | 300-650 MPa |
| Key Applications | C11000 Electrolytic Tough Pitch (ETP) copper is the most common commercially pure copper grade, containing ≥99.90% Cu wi... | C26000 Cartridge Brass (70% Cu, 30% Zn) is the most ductile brass composition — it can be deep-drawn, spun, and cold-for... |
International Equivalents
| C11000 ETP Copper: E Equivalents | C26000 Cartridge Bra Equivalents |
|---|---|
| EN Cu-ETP | CuZn30 |
| CW004A | EN CW505L |
| JIS C1100 | JIS C2600 |
| T2 Copper | GB H70 |
| ISO Cu-ETP | — |
How to Choose
| Choose C11000 ETP Copper: Electr when... | C11000 ETP copper delivers 101% IACS conductivity—the standard for electrical applications. |
| Choose C26000 Cartridge Brass (7 when... | C26000 cartridge brass (70/30) offers better strength, machinability, and deep-drawability for plumbing, musical instruments, and decorative hardware.. |
Selection Guide
Choose C11000 ETP copper when maximum electrical or thermal conductivity is the primary requirement — bus bars, wiring, heat exchangers, and grounding systems. Choose C26000 cartridge brass when you need a combination of formability, machinability, corrosion resistance, and aesthetic gold-colored finish — plumbing fittings, decorative hardware, and deep-drawn components.
Key Decision Factors
- Conductivity — C11000 provides 101% IACS electrical conductivity; C26000 only 28% IACS. This 3.6× difference makes copper irreplaceable for electrical applications
- Formability — C26000 deep-draws far better than pure copper; it is the standard for complex drawn shapes like cartridge cases
- Machinability — C26000 machines better than pure copper (40% vs 20% machinability rating); for leaded brass (C36000) machinability reaches 100%
- Cost — C11000 costs roughly the same per kg as C26000; selection is driven by application requirements, not material cost
When to Use Each
Use C11000 ETP Copper: E for:
C11000 delivers 101% IACS conductivity — the standard for electrical applications. No brass alloy comes close to this conductivity level.
C11000's conductivity and corrosion resistance in soil make it standard for electrical grounding systems per NEC and UL 467.
C11000's thermal conductivity (391 W/m·K) makes it ideal for heat exchanger tubes and fins where maximum heat transfer efficiency is required.
Use C26000 Cartridge Bra for:
C26000 (70/30 brass) has the highest deep-drawability of any copper alloy — standard for cartridge cases, lamp shells, and decorative drawn components.
C26000's combination of strength, corrosion resistance to water, and machinability makes it standard for plumbing fittings, valve bodies, and water connectors.
C26000's warm gold color, ability to be polished, lacquered, or plated, and moderate cost make it the standard for decorative door hardware, lighting fixtures, and furniture trim.
Frequently Asked Questions
What is the main difference between C11000 ETP Copper: Electrolyti and C26000 Cartridge Brass (70/30)?
C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use (ASTM B152/B187) provides 69 MPa (10 ksi) annealed; 310 MPa (45 ksi) hard yield strength at 8.94 g/cm³ density, while C26000 Cartridge Brass (70/30): The Cold-Workable Standard (ASTM B36) delivers 75-420 MPa at 8.53 g/cm³. The choice depends on whether your application prioritizes maximum electrical conductivity (bus bars, wiring) or formability, corrosion resistance, and aesthetic finish.
Can C11000 ETP Copper: Electrolyti be substituted for C26000 Cartridge Brass (70/30)?
Direct substitution is generally not recommended as these materials belong to different categories (Copper Alloy vs Brass & Bronze) with fundamentally different properties. Consult a materials engineer for application-specific guidance.
What does ETP mean in C11000 ETP copper?
ETP stands for Electrolytic Tough Pitch — the standard manufacturing method for copper. The copper is electrolytically refined and cast with 0.02-0.04% oxygen content. The oxygen reacts with impurities, keeping conductivity at 101% IACS. ETP copper should not be heated above 400°C in hydrogen-containing atmospheres, as hydrogen reacts with the oxygen to form steam, causing embrittlement (hydrogen embrittlement).
Why is C26000 called 'cartridge brass'?
C26000 (70% Cu, 30% Zn) earned the name 'cartridge brass' because its 70/30 composition provides the optimal combination of deep-drawability and strength for manufacturing ammunition cartridge cases. The 70/30 ratio produces a single-phase α-brass microstructure with maximum ductility — it can be drawn to over 50% reduction without cracking.
Can C11000 copper be used for water plumbing?
Yes. C11000 copper tubing (Type K, L, M) is the traditional standard for potable water supply lines per ASTM B88. It resists corrosion in freshwater, is bacteriostatic, and has a 50+ year service history. However, copper prices have made PEX and CPVC competitive alternatives for residential plumbing.
What is dezincification and does it affect C26000?
Dezincification is selective leaching of zinc from brass in certain water conditions, leaving a porous copper residue. C26000 is susceptible to dezincification in warm, stagnant, or slightly acidic water. For plumbing applications prone to dezincification, specify DZR (dezincification-resistant) brass grades containing arsenic (C35330 or CW602N) per BS EN 12164/12165.
How does the cost of copper compare to brass?
Per kilogram, copper and 70/30 brass are similarly priced because brass's zinc content (cheaper than copper) roughly offsets the fabrication cost. However, copper's higher density (8.96 vs 8.53 g/cm³ for brass) means slightly more weight per volume. The real cost difference comes from application — electrical applications require pure copper; no substitution is possible.